[Purpose] The purpose of this study was to investigate the effects of the modified constraint-induced therapy (mCIT) combined with mental practice (MP) on patients with chronic stroke. [Subjects] The subjects were 26 patients with chronic stroke. [Methods] Patients were randomly assigned to the mCIMT + MP group or the MP group. All subjects were administered mCIT consisting of (1) therapy emphasizing affected arm use in functional activities 5 days/week for 6 weeks and (2) 4 hours of restraint of the less affected arm 5 days/week. The mCIT + MP subjects received 30-minute MP sessions provided directly after therapy sessions. To compare the two groups, the Action Research Arm Test (ARAT), Fugl-Meyer Assessment of Motor Recovery after stroke (FM), and Korean version of Modified Barthel Index (K-MBI) were performed. [Results] Both groups showed significant improvement in ARAT, FM, and K-MBI after the interventions. Also, there were significant difference in ARAT, FM, and K-MBI between the two groups. [Conclusion] mCIT remains a promising intervention. However, its efficacy appears to be enhanced by use of MP after mCIT clinical sessions.